title: Feasibility and test-retest reliability of measuring lower‑limb strength in young children with cerebral palsy.
abstract: BACKGROUND
  Quantifying leg muscle strength in young children with cerebral palsy (CP) is essential for identifying muscle groups for treatment and for monitoring progress.
  
  
  OBJECTIVE
  To study the feasibility, intratester reliability and the optimal test design (number of test occasions and repetitions) of measuring lower-limb strength with handheld dynamometry (HHD) and dynamic ankle plantar flexor strength with the standing heel-rise (SH) test in 3-10 year aged children with CP.
  
  
  METHODS
  Test-retest design.
  
  
  METHODS
  Rehabilitation centre, special needs school for children with disabilities, and university medical centre.
  
  
  METHODS
  Knee extensor, hip abductor and calf muscle strength was assessed in 20 ambulatory children with spastic CP (3-5 years [N.=10] and 6-10 years [N.=10]) on two test occasions. Intraclass correlation coefficients (ICC) and Smallest Detectable Differences (SDD) were calculated to determine the optimal test design for detecting changes in strength.
  
  
  RESULTS
  All isometric strength tests had acceptable SDDs (9-30%), when taking the mean values of 2-3 test occasions (separate days) and 2-3 repetitions. The one-leg SH test had large SDDs (40-128% for younger group, 23-48% for older group).
  
  
  CONCLUSIONS
  Isometric strength (improvements) can only be measured reliably with HHD in young children with CP when the average values over at least 2 test occasions are taken. Reliability of the SH test is not sufficient for measuring individual changes in dynamic muscle strength in the younger children.
  
  
  CONCLUSIONS
  Results of this study can be used to determine the optimal number of test occasions and repetitions for reliable HHD measurements depending on expected changes, muscle group and age in 3-10 year old children with CP.
authors.affiliation: Amsterdam Rehabilitation Research Center / Reade Amsterdam, The Netherlands - l.v.vulpen@reade.nl.
authors.forename: L F
authors.initials: LF
authors.lastname: Van Vulpen
authors.forename: S
authors.initials: S
authors.lastname: De Groot
authors.forename: J G
authors.initials: JG
authors.lastname: Becher
authors.forename: G S
authors.initials: GS
authors.lastname: De Wolf
authors.forename: A J
authors.initials: AJ
authors.lastname: Dallmeijer
mesh_terms: D000293:Adolescent; D002547:Cerebral Palsy / Q000503:physiopathology*; D002648:Child; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D009426:Netherlands; D015588:Observer Variation; D015203:Reproducibility of Results